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(No Model.)

T. VA & J. A. SBELY.

TELEPHONE EXCHANGE SIGNALING.

' Patented July 10 1888.

I UNITED STATES- PATENT OF ICE.

'rnnoponn N. VAIIJ, or BOSTON, MASSACHUSETTS, AND JOHN'A. SEELY, or N W YORK, N. Y.

TELEPHONE-EXCHANGE.SlGNALING.

srncxrrcn'rxon forming part of Letters Patent noj 385.978, dated July 10,1888.

Application filed Murrh i, uses.

.115 the use of special indicating devices to receive calls or rcqu'ests from sub-stations, and

we only use an aimunciator for clearing-out set.

purposes. r 7

Our improvement consists in connecting every sub station line of a gronpwith an operators head telephone at a central station,and in terminating every sub station line of a. group in a flexible connecting-cord normally resting by force of a gravity take-up upon con '2 doctors occon'nections forming the terminals of an operators head telephone. By this means no preliminary signal is necessary, the sub station merely holding his telephone and speaking into the transmitterhis own'num- 39 her or designation and the number or designation of the. sub-station required. At the sub-station we provide means for including a generator of electricity yielding a steady current in the circuit. This-is to be done i immediately after speaking or announcing the correspondent desired, and the call being received at the central station the operator lifts the jack-plhgformi-ng the terminal of thccalling-line preparatory to placing it in 0 the jack of-thc callcd-forstations lineJ The act of lifting the plug tcmporarily breaks the air-- cuit, and the armature of the bell-magnet-at the sub-station drops oil, sounding oneor more strokes, signifying to the sub-station that the eall is received and acted. upon-that is, it-

operates as a rcturi i-signal to the request.

The accompanying drawing illustrates our invention. q 1 is'a subscrihers circuit, here shown as a metallic circuit uniting ceutral'station, A, and sub-station B. At'At-here is a multiple-board I Serial No. 205,751. (X0 modem arrangement. G, G, and G are three springjacks on three separate boards, through each and all of which the wire 1 passes. This cir'-, cuit 1 belongs to a group assigned to board G, 5 5 let ussnppose. It terminates in a flexible cord, 0, and jack plug" P, held in position by a v gravitytake-up, w. The two conductors forming oppositesides of the metallic circuitterminate in electrical contacts 20 21 onthe-base- 6o oftheplug. w

" 22.and 23 are electrical contacts forming the terminals of a local circuit containing an operators headtele'phoneset, '1. These contacts are in such a position that at ntacts 20 21 of the plug rest thereon when-the' lng is in its normal position, as shown, so the; the circuit 1 normallyineludes. anop'oratorr, telephone- At thesub-st'ationB there is a telephone-sch T, consisting of a hand-telephone, a contact-varying transmitter with-its local battery, known and the well arrangement of gravity-switch for changing. the main-line'circnit from the -bell branch to the telephone branch, and vice 7 versa, andt'or making and breaking the transm'itter local circuit. In addition it is furnished with. a tumbler-lever, z, and special battery-connection .17 for connectingbattery to. line when the gravity-switch is moving inone direction only to operate as a -ring-of signal, this arrangement and apps ratus being described and claimed in an appication for United States Letters Patent filed-b3 us onFebwary-25, 1888. At the sub-stati'cu'there is also a supplementary switch-arm, a:, normally closing contacts 12 13 in the telephone branch and 1445 intheci'rcuit of the local battery. Lever a carrieselectrical connections 8 in two 'insulated sections, one of which (the lower) is o electrically connected to arm a, the other, 9, is insulated from arm a.

10 is a fixed electrical contact or strip of' metal, which, when a is depressed, unites con tacts 8 and 9. y

The'described apparatus operates as follows: Telephone T at the central stati'on'is continu- 'ously 'i-n audible distance with respect to the operator. The sub-station lifts his telephone and vocally announces his own number and that of the desired station. He then immediately depresses lever a. This throws the local battery of the sub-station into the main line, circuit being via 1, local battery 14 9 10 8 a to 1 through the plngand telephone at the central station. The circuit is closed and armature of bell C is attracted. The operator at the central station has heard the call, however, and immediately lifts plug P preparatory to placing it in thev called-for-line jack, but this act breaks the circuit 1 1 temporarily. the armature .of bellC falls off, striking the gong, and this indicates to the sub station that his call was received and acted upon. He then allows the spring rctractedarm a to resume its normal position and, carries on a con- 1 versation with the distant station. When through his communication, the act of restoring the telephone temporarily connects i and 17,, thus again including the local battery in the main line. This drops the annnnciator n and the central-station operator restores the normal conditions. There is provided at the central station devices r r for ringing in either direction through the batteries b b, and there is a looping-in device, L. We do not herein claim the ariangeinentof apparatus shown and described at the substation, nor that shown and described at the central station, as that forms the subject-matter of applications filed by us on or about February 25, 1888; but

What we claim, and desire to seen re by Let.-.

cnit, consisting of a pivoted arm operating a said stations, telephone-instruments in said. 50.

circuit at both stations, a flexible conductor at the central station normally resting upon a seetion'of conductor to complete said circuit, a' generator of electricity at the substation, and a switch for including said generator in the circuit, all arranged substantially as de scribed, whereby a change in the normal position of the flexible cord sounds a signal at the substation.

3. The combination of two telephone-stations, an electrical conductor uniting said stations, a fragmentof said conductor containing an electromagnetic indicating-instrument at each station, a device at one. station-sa.y the firstf0r connecting and disconnecting said fragment with respect to the main circuit, a generator of electricity, and adevice for connecting anddiseonneeting said generator with respect to said conductor at the second station, all arranged and operating substantially as described, whereby a variation in connection of the line-fragmeutatthefirst-station changes the circuit of the generator and sounds a s'ige nal at the second station.

THEO. N. VAIL. JOHN A. SEELY.

Witnesses:

WM. H. BAKER, J. MILTON FERRY, Jr. 

